This invention relates to radiation curable and radiation cured coatings such as cast films, inks, varnishes and release coatings, methods of making the same, and prepolymer materials suitable for making such coatings. These coatings are curable by ultraviolet radiation as well as by plasma arc and an electron beam radiation, which for the present purposes shall be deemed to be a form of radiation curing.
Coatings and inks for paper, foil, film, panels, tiles and the like are desired which can be readily applied and which, after application, are tough, flexible, solvent resistant and abrasion resistant. Elimination of solvents to reduce cost, to avoid pollution, and to achieve improved properties is desirable. Release surfaces of low adhesion are useful for transfer printing, for temporary protective cover sheets for pressure-sensitive adhesives, and to facilitate handling of multiple articles in machinery or the like.
Known radiation curable coatings useful for other purposes have been deficient in one or more of the above described criteria. Either they have required long exposures to radiation, especially ultraviolet light, or they have limited strength, abrasion and solvent resistance. Suitable release coatings heretofore known have required use of materials such as waxes or resins which inherently have release properties and have been applied as hot-melts or solvent solutions.